[Stoves] First test of the Maputo Ceramic Stove

[Crispin Pemberton-Pigott]

Dear Friends
 
I have completed a test of the first fully formed Maputo Ceramic Stove (MCS)
with 3 litres of water and initially a bit more than 300 gm of charcoal.
The unit in the pictures is the final version.
 
See pictures at: http://bioenergylists.org/en/mcs200_8_20_2006
 
The test was done without any skirt or under-tray to improve efficiency,
just a pot and lid sitting on a simple stove.
 
 
The water boiled in exactly 30 minutes even though the stove body was wet
from being washed (oops).
 
The specific fuel consumption calculated on the basis of water remaining at
the time of boiling (good idea) and water remaining at the end of the simmer
(something I think is weird) is:
 
48 gm per litre of water boiled
16.5 gm per litre simmered at 1 degree below the local boiling point for 45
minutes.
 
This translates into about 324 gm to boil and simmer 5 litres of water,
depending on how you calculate it.
 
The stove was easy to use.  I closed the air hole when it boiled and
otherwise did not touch anything at any time.
 
There was more than 140 gm of charcoal left in the stove at the end of the
test.  This means it had too much in it to begin with. I was unable to get
the temperature to drop below almost the boiling point so I think if it was
done again with perhaps 200 or 250 gm of fuel it would come out with a
better figure.
 
The stove in the photos will cost about $3 to manufacture profitably.  The
material is very low thermal expansion PK11 clay mix fired at 1150 degrees.
The whole stove weighs 2230 grammes.  The material cost about US$0.40.  The
grate is removable.  The two parts can be formed in a manual press like the
Ring Maker.
 
I did not have a chance to check the CO figures.  Earlier tests of the
system in prototype form showed the CO to be much lower than a JIKO so I
guess that will still be the case.
 
Best regards
Crispin